The present invention relates to a heat accumulator, in particular a latent heat accumulator. More particularly, it relates to a heat accumulator which has an interior envelope with an accumulator core and an exterior envelope surrounding the interior envelope at a distance to form an insulating chamber, with lines passing through the insulating chamber.
In a known heat accumulator of this type (DE-OS 40 07 004), the line sections led through the insulation chamber are made of plastic, because its heat conducting capability is less than that of metal lines. For comparison, continuous, one-piece aluminum pipes, for example, can be cited as metal lines. The design of the line section in plastic has many disadvantages. For one, no permanent temperature stability is assured, particularly if the heat-conveying medium is at high temperature during operation. It is furthermore disadvantageous that line sections made of plastic cannot be fastened sealingly, preferably vacuum-sealed, at all or only with great effort and doubtful results on the interior envelope and at the place where these line sections pass through the exterior envelope, fastened on the outer envelope. With vacuum-insulated heat accumulators, the material of the line sections must be sealed against diffusion, i.e. suitable for a vacuum. Plastic cannot lastingly meet such requirements. In addition, plastic can also not withstand the prevailing mechanical stresses, for example oscillation stresses, in the long run.